Automatic ball retrieving device



Feb. 2, 1965 E. R. DAVIS 3,l68;3l2

AUTOMATIC BALL RETRIEVING DEVICE Filed Oct. 11, 1961 3 Sheets-Sheet 1 INVENTOR. EDWARD R. DAVIS BY w pm, W

ATTORNEYS Feb. 2, 1965 E. R. DAVIS 3,168,312

. AUTOMATIC BALL RETRIEVING DEVICE Filed Oct. 11, 1961 3 Sheets-Sheet 2 INVENTOR. EDWARD R DAVIS ATTORNEYS Feb. 2, 1965 R. DAVIS 3,163,312

AUTOMATIC BALL RETRIEVING DEVICE Filed Oct. 11, 1961 3 Sheets-Sheet 3 INVENTOR. EDWARD R DAVIS BY S AN, gm

ATTORNEYS United States Patent 3,168,312 AUTOMATIC BALL RETRIEVING DEVICE Edward R. Davis, R0. Box 558, perry, Okla. Filed Get. 11, 1961, Ser. No. 144,362 4 Claims. (Cl. 273-26) This invention relates to a device for automatically retrieving a ball which is thrown or projected away from a point to which it is desired to subsequently return the ball.

More particularly, but not by way of limitation, the present invention relates to a tethered ball apparatus which is effective to permit the ball to be struck by a hat or club and driven away from the point to which it is tethered, and then to automatically return the ball to the point from which it has been driven.

In a number of games and sports, it is the practice to strike a ball with some type of implement, such as a club, bat or racket. In most instances, the skill of the participants in such sports is indicated by the distance which the ball is driven, or by the directional accuracy with which it is driven. When these sports are played competitively with other players participiating, it is usually unnecessary for the player who strikes the ball to follow after the ball and retrieve it and return to the point at which it was struck, since the other players on the playing field will, as apart of the game, return the ball to its place of origin. In other types of sports, such as golf, in actual competition, the golfer does not expect return of the golf ball to the place from which it was hit, but rather, will follow it to the location where its motion has stopped.

It is desirable in practicing sports of the type described (where the benefit of other participating players is not available) to provide some means for returning the ball after it has been struck to the practicing player in order that wasted time and energy need not be expended in following up and retrieving the ball. A number of devices have previously been contrived for bringing a golf ball or a baseball which has been struck to the position from which it was initially propelled. However, a number of disadvantages have characterized such devices which makes their utilization difiicult, unsatisfactory, or, in some cases, even dangerous. For example, the line or string which is attached to the balls in most of such devices, is payed out in such a way that the shaft or drum upon which it is reeled acquires a speed of rotation such that the string is unwound faster than the ball travels as it approaches the end of its course. This results in the development of excessive slack in the string or line, leading to fouling or snagging upon objects such as rocks or shrubbery.

Another disadvantage which has characterized some of the types of devices previously utilized for practicing games and sports in which a ball is struck, is the utilization in such devices of a retrieving apparatus which returns the ball to its origin immediately after it has reached the full extent of its trajectory. This does not allow the player sufiicient time for observation of the effect of his strokethat is, the distance which he has hit the ball, or the direc tion and manner in which he has hit it. Moreover, a rapid and immediate return of the ball to its origin after it has been hit is dangerous to the practicing player since he may be unable to extricate himself from the path of the returning ball quickly enough to avoid being struck.

A further problem which has been encountered in many previous types of ball retrieving devices is the adaptation of such devices to one particular type of ball and striking implement. Thus, the type of line and retrieving mechanism which is utilized for a tennis ball cannot be utilized for a much heavier baseball or softball since the momentum developed by the latter types of balls in flight demand a heavier tether line, and a more strongly loaded retrieving mechanism than does the lighter tennis ball.

The present invention comprises an automatic ball re- 3,168,3l2 Patented Feb. 2, 1965 there is no danger of injury to the practicing player if he should fail to move out of its path.

An additional feature of the present invention is the utilization in the ball retrieving device of the invention of a soft braking mechanism which retards the rotational speed of the drum upon which the tether line is wound sufficiently to assure that the line is not payed out faster than the ball is advancing. The braking device may also be utilized to retard the rate of return of the ball to any degree desired.

Broadly, the automatic ball retrieving device of the present invention comprises a drum which is driven by a highly flexible elastic member, preferably a rubber band; means for adjusting the tension of the rubber band to control the rate at which the ball is retrieved; a ratchet mechanism for preventing the rotation of the drum in the direction required to retrieve the ball; and braking means for retarding the rotation of the drum to prevent the development of excessive slack in the line attached to the ball when the movement of the ball away from the drum is decelerated.

From the foregoing discussion, it will be apparent that a major object of the present invention is to provide an automatic ball retrieving device which may be used for practicing a variety of sports and which may be more safely utilized than previous devices of this type.

An additional object of the present invention is to provide an automatic ball retrieving device which permits a ball of the type used in various sports to be struck by the types of instrument used in the sports and propelled through a considerable distance without the development of excessive slack in the line which is utilized to retrieve the ball.

A further object of the invention is to provide an auto matic ball retrieving device which is simple in construc tion, yet is characterized by a long and trouble-free operating life.

Other objects and advantages will become apparent from a further reading of the following specification in conjunction with a perusal of the accompanying drawings which illustrate my invention.

In the drawings:

FIG. 1 is a view in elevation of the invention showing the way it appears when positioned in a vertically upright position ready for utilization in practicing the sport of golf.

FIG. 2 is a view partially in section and partially in elevation of the retrieving mechanism of the invention.

FIG. 3 is a view in elevation of the housing which contains the drum of the retrieving mechanism with a portion of the housing broken away to illustrate the ratchet mechanism which cooperates with the retrieving drum.

FIG. 4 is a View in elevation of a modified embodiment of the invention with portions of various housings broken away to illustrate the nature of the modifications.

FIG. 5 is a view similar to FIG. 3 and illustrates a modification of the present invention in which the braking and ratchet mechanisms are integrated.

FIG. 6 is a view in section taken along lines 66 of FIG. 5.

Referring now to the drawings in detail, and particularly to FIG. 1, the automatic ball-retrieving device of the present invention comprises a housing 10 in which the retrieving mechanism is located. A line 12 is connected between the retrieving mechanism and passes through an aperture 15 formed in the housing 10. The housing includes an elongated hollow cylindrical arm portion 16 which is secured to the top of a vertical standard 18 which may be driven into the ground to support the housing 10 and the retrieving mechanism contained therein in an elevated position. In this way, the ball 14 may be positioned on the ground such as for the purpose of practicing golf, or may be suspended midway between the housing 10 and the surface of the ground, such as for baseball batting practice. a

In FIG. 2, the manner in which the retrieving mechanism is mounted in the housing 16 is illustrated. The retrieving mechanism consists basically of a spring-driven drum, designated generally by reference character 29, which is rotatably mounted in the housing 10 by means of an angular contact ball bearing 22. The drum 20 comprises a pair of abutting circular plates 24 and 26, which are secured to each other by suitable means, such as by the rivets 28. Adjacent its periphery, each of the plates 24 and 26 is bent outwardly and upwardly so that when they are riveted together, the two plates 24 and 26 form a channel 30 extending circumferentially around the drum 20. The string 12 is received in the channel 30 when it isreeled on the drum 20 as shown in FIG. 2.

In a preferred embodiment of the invention, the drum 20 is retained in its supporting bearing 22 by means of a hub 31 which is pressed'out of the plate 24. The drum 2i) is spring-driven by means of a rubber band 32 which is attached to a hook 34 pressed out of the plate 26 and also to a hook 36 which is secured to a cap member 38 rotatably fitted over one end of the hollow cylindrical arm portion 16 of the housing 10. The cap member 38 is provided with indentations 4%? located in circumferentially spaced relation to each other around the free edge of the cap member which is positioned inwardly from the end of the hollow arm portion 16. A projection 41 is positioned on the outer peripheral surface of the hollow arm portion 16 to cooperate with the indentations 40 in preventing rotation of the cap a member 38.

indicated by reference character 42 to form a ratchet which cooperates with a pawl 44 to prevent the drum,

it from rotating in one direction. The pawl 44 is mounted in the housing 10 by means of a pivot pin 46 and is constructed to facilitate manual pivotation to release the drum 20 for rotation in either a clockwise or counterclockwise direction. With the arrangement depicted in FIG. 3, the line 12 may be payed out through the opening formed in the housing It by rotation of the drum in a clockwise direction. Thus, when the ball 14 is struck and propelled away from the housing 10, the drum will rotate freely to pay out the line 12 as required to permit the ball to travel through its normal trajectory. However, after the ball 14 has reached the end of its travel, the pawl 44 and ratchet mechanism provided by the notches 42 on the plate 24 will prevent the drum 20 from being rotated under the influence of the rubber band 32 to retrieve the ball.

As a final feature of the preferred embodiment of the invention, a frictional braking means, designated generally by reference character Si), is provided for retarding the rotation of the drum 20 and is illustrated in FIG. 2.. The. frictionalv braking means 50 includes a set screw 52 which is threaded throughthe outer face of the housing 10, and which extends substantially normal to the circular plate 26. A spring'metal' brake shoe 54 is secured to the inside of the housing 10 and is positioned relative to the drum 20 so that the shoe may be biased against the drum by threading the set screw 52 into the housing 10. The degree of drag which is imposed upon the drum 20 by the frictional braking element 50 will thus depend upon the extent to which the set screw 52 is tightened. The manner in which the frictional braking element 5% is utilized in the operation of the invention is hereinafter described in greater detail.

Operation In the operation of the automatic ball-retrieving device of the present invention, it is necessary at the outset to adjust the torque which is applied to the drum 20 by the rubber band 32. The torque which initially acts through the rubber band 32 on the drum 20, will be hereinafter referred to as the initial torque and its magnitude is dependent upon the amount of torque which is applied to the rubber band 32 by the rotation of the cap member 38 at one end of the hollow arm member 16. Thus, with the pawl 44 engaging the notches 42 in the plate 24 of the drum 2t), rotation of the cap member 38' in a counterclockwise direction will store potential energy in the rubber band 32. The magnitude of this stored energy will, in turn, determine the resistance to rotation of the drum 20 in a clockwise direction, and also the speed with which the drum 29 will be rotated in the counterclockwise direction when the pawl 44 is pivoted upwardly to release the drum 20. This restorative force which.

is stored in the rubber band 32 may be maintained by engaging one of the indentations 40 in the cap member 38 with the projection 41 formed on the outer periphery of the hollow arm member 16. In setting the cap member 38 to the required position to preload the rubber band 32 to the extent desired, factors such as the weight of the ball 14 which is to be retrieved, and the rate at which it is desired to retrieve the ball are considered.

After the cap member 38 has been adjusted to the desired position, the ball 14 is pulled away from the housing 10 until it is in the position where it will be struck by the implement to be used in practicing a certain sport. Thus, if it is desired to practice batting a baseball, the ball 14 will, of course, be a baseball, and will be positioned within a theoretical strike zone between the housing 10 and the ground. On the other hand, if the ball 14 is a golf ball, enough of the line 12 will be unreeled from the drum 20 to permit the ball 14 to rest upon the ground. The ball 14 is then in a position to be struck by a driving wood or pitching iron of the golfer. It will be apparent that other types of balls, such as tennis balls or footballs might also be attached through the line 12 to the retrieving mechanism of the present invention.

After the ball 14 is struck by the bat, club, or racket 0f the practicing player, it is propelled away from the housing 16 so that the line 12 is unreeled from the drum 20 which is permitted to turn in an unreeling direction by the pawl 44. As the drum 20 turns, the rubber band 32 is twisted to store potentialenergy therein to be utilized in retrieving the ball 14. Of course, the further the ball 14 moves away from the housing 16, the greater 7 becomes the resistance offered to its further travel by the rubber band 32. However, by utilizing a rubber band of the proper dimensions, and by properly adjusting the initial torque applied to the drum 20 through the rubber band, the decelerating influence of the twisted band can be reduced enough that thetalteration of the pattern of flight and distance of travel of the ball will not be so great as to negate the value of the device in permitting the player to observe the effect of his stroke.

After the ball 14 strikes the ground, it may happen that certain obstacles such as high grass, shrubbery, rocks, etc., will retard its movement faster than the rotational movement of the drum 2%) is retarded by the rubber band 32. In such event, the line 12 may be payed out from the drum 20 so fast that a considerable amount of slack will develop in the line between the housing 10 and the ball 14. The development of this slack may be prevented by imposing a slight frictional drag upon the drum 20 by means of the frictional braking means 50. This feature of the invention is of enhanced importance when the ball retrieving device is utilized for practicing sports of the type in which the ball 14 may tend to return toward the housing 10, or at least nearly stop dead at the instant of striking the ground after its flight through the air. Examples of such situations are place kicking practice in football and chipping practice in golf.

When the forward momentum of the ball 14 has been lost, the pawl 44 engages one of the notches 42 in the plate 24 of the drum 2t and prevents the reverse rotation of the drum 26 by the rubber band 32. The ball thus remains at rest at its farthest point of travel so that the practicing player can observe the direction it has taken and the distance it has traveled. Suitable means are preferably provided for registering the distance of travel, such as a metering device operated by rotation of the drum 2%, or perhaps merely suitable markings spaced at known intervals of distance along the line 12.

After the player has had an opportunity to observe the complete effect of his stroke on the ball 14, he may then retrieve the ball by pivoting the pawl 44 to its upward position. This releases the drum 20 for rotation in the proper direction for reeling up the line 26. A torque is immediately applied to the drum 20 by the rubber band 32, causing the drum 29 to rotate and the line 12 to be reeled up on the drum. The ball 14 is thus returned to the housing so that it may be placed by the prac ticing player in position for another stroke.

From What has previously been said, it will be apparent that prior to releasing the pawl 44, the player may adjust the retrieving mechanism to control the rate of return of the ball 14 to its point of origin. This rate of return may be controlled in two ways. First, the rate of acceleration of the ball from its at-rest status to its maximum return velocity may be varied by adjusting the cap member 38 to increase or decrease the potential energy stored in the rubber band 32. Second, the velocity of the ball at any instant during its return may be varied by adjusting the set screw 52 of the frictional braking device 56 so as to increase or decrease the frictional drag imposed on the drum 20 as it rotates. The two control features may be used conjunctively to achieve the most suitable type of return for the particular ball being used. In general, it will be desirable in the case of relatively heavy balls to store a large amount of potential energy in the rubber band 32 while setting up relatively tightly on the set screw 52. This assures that sutficient force will be available to overcome the inertia of the motionless ball, without the ball being accelerated during its return to such a velocity that it becomes dangerous to the player or tends to overshoot the housing 10.

A slightly different mode of operation may be employed when it is desired to have one person pitch or throw a ball to be struck by a second person. In this situation, an amount of the line 12 equal to the distance from pitcher to batter is unreeled from the drum 2t) and all torque is removed from the rubber band 32. The cap member 38 is next engaged with the projection 41. Then when the ball 14 is pitched, no resistance is offered to its movement by the rubber band 32 while it is en route from pitcher to batter. It also moves freely (except for friction and the weight of the line 12) when it is hit back by the batter until it has traveled a distance equal to the distance between pitcher and batter. After this distance is traversed, the rubber band 32 commences to be twisted and the above described action then takes place. However, instead of the ball 14 being returned to the batter, it will be returned to the pitcher.

A modified embodiment of the invention is illustrated in FIG. 4. In general, the retrieving mechanism of the modified embodiment is similar to that shown in FIGS. 1 through 3, and like elements of the FIG. 4 embodiment have been designated by reference characters corresponding to their counterpart elements in the preferred embodiment shown in FIGS. 1 through 3. The FIG. 4 embodi- Inent, however, employs a slightly different type of driving mechanism for the drum 20. Instead of utilizing the hook 34 which is pressed out of the plate 26 of the drum 20 in the preferred embodiment, an elongated cylindrical shaft 55 is coaxially secured to the drum and extends from one side thereof through the hollow cylindrical arm portion 16. The end of the shaft 55 opposite its end which is secured to the drum 20 is journaled in the closed end of the hollow arm portion 16. An elastic member 56, such as a strip of rubber, is secured at one of its ends to a point on the periphery of the shaft 55. The other end of the elastic member 56 is extended down into the vertical standard 18, which, in the case of the modified embodiment illustrated in FIG. 4, is hollow, and is secured to a shaft 57 which extends diametrically through the vertical standard 18 and is rotatably journaled therein. The shaft 57 is secured at its end which projects outside the hollow vertical standard 18 to a small circular plate 58. The plate 58 carries a handle 59 which facilitates the rotation of the plate and, in turn, the rotation of the shaft 57. A locking pin 60 slidably extends through apertures (not seen) formed in the plate 58 and is adapted to engage aligned apertures formed in the hollow vertical standard 18.

From the foregoing description of the modified embodiment shown in FIG. 4, it will be apparent that the circular plate 58 and its associated locking pin 60 correspond in function to the cap member 38 of the preferred embodiment of the invention. These elements, therefore, may be utilized to adjust the initial torque which acts upon the drum 20, and also to control the rate at which the ball is returned toward the housing 10. Rotation of the drum 20 as the ball is driven away from the housing 10 will cause the shaft 55 to be rotated in a direction such that the elastic member 56 is reeled thereupon. Thus, the elastic deformation of the elastic member 56 by such movement will be effective to store potential energy in this member of sufiicient magnitude to effect the return of the ball toward the housing 10 when the pawl 44 is disengaged from the notches 42 of the drum 20.

An additional modified embodiment of the present invention is illustrated in FIGS. 5 and 6. An elongated spring metal member 64 is secured to an outer face of the housing 10 by means of a suitable pin or rivet 66 which is rotatably journaled in the housing. A set screw 68 is threaded through a medial portion of the spring metal member 64 and carries a knurled head 70. The set screw 68 passes through an elongated slot 72 formed in the housing 10, which slot is dimensioned to perrm't the set screw 68 to be pivoted through a small are as the spring metal member 64 is pivoted with the rivet 66.

On the inside of the housing 10, a second elongated spring metal member 74 is secured adjacent one of its ends 74a to the rivet 66, and extends into close proximity to the drum 20 at its other end 7411. Intermediate the ends 74a and 74b of the elongated spring metal member 74, the spring metal member is contacted by the end of the set screw 68 so that as the set screw is threaded into the spring metal member 64 outside the housing 10, the spring metal member 74 is biased into contact with the drum 20.

In order to permit the spring metal member 74 to function both as a ratchet-engaging pawl for preventing rotation of the drum in one direction, and also as a braking element, a plurality of bosses 76 are formed on the monoplanar face of the drum 20 which extends parallel to the wall of the housing It to which the spring metal member 74 is secured. The bosses 76 are disposed in spaced relation from each other along a circle which is concentric with respect to the axis of rotation of the drum 20. Each of the bosses 76 is provided with a shoulder portion 76a which extends normal to the face of the drum 20, and also with a tapering body portion 765 which tapers gradually from the shoulder 76a into the V trated in FIGS; and 6, the mechanism formed by'the spring metal members 64 and 74 and the set screw 68 may be utilized in conjunction with the bosses 76 to provide either a braking function, a pawl and ratchet function preventing rotation of the drum in one direction, or neither the braking nor the pawl and ratchet function. When the inside spring metal member 74 has been aligned with the bosses 76 by pivoting the spring metal members 64 and 74 to the proper position, the set screw 68 may then be screwed inwardly to cause the end' 7412 of the spring metal member 74 to bear against the face of the drum with sufiicient compression to provide the desired braking action. The end 74b of the spring metal member 74 will ride smoothly over the bosses 76 while the drum is rotating in one direction, but will'prevent rotation of the drum 20 in the opposite direction by virtue of the engagement of the end 74b'of the spring metal member 74 with the abrupt shoulder 76a formed on the bosses 76. By pivoting the spring metal member 64 sui'ficiently to move the set screw 68 to the other end of slot 72, the drum engaging end 74b of the spring metal member 74 may be moved out of alignment with the bosses 76 so that the drum may be allowed to rotate freely in either direction except for such braking action as it may be desirable to apply.

Although only two embodiments of the present invention have been illustrated and described by the drawings and the foregoing specification, it will be apparent to those skilled in the art that certain modifications in the described structure may be easily, and perhay ""fvantageously, effected Without departing from the invention principles herein disclosed for the first time. Insofar as such modifications do not depart from the utilization of such principles, they are considered to be comprehended by the spirit and 'scope'of the invention as defined by the following claims.

I claim:

1. An automatic ball retrieving device comprising:

(a) a drum;

([2) means rotatably supporting said drum vertically spaced from the ground;

(0) a tensionable elongated member connected at one of its ends to said drum for driving said drum in rotation;

(d) a line adapted to be connected at one of its ends to the ball to be retrieved and connected at its other end to the periphery of said drum, said line being of a length such that the line can be extended from said drum to the ground; and f (2) means for introducing a predetermined degree of initial tension into said tensionable member whereby a ball connected to one end of said line and supported by'said line can be supported at variable distances from said drum and above the ground in playing a variety of different games with different types of balls.

2; An automatic ball retrieving device comprising:

(a) a drum; 7

(b') means rotatably supporting said drum and adapted for mounting said drum in vertically spaced relation to the ground;

(c) an elongated elastomeric band connected by the bight at one ofits ends to said drum for driving said drum in rotation;

(d) a line adapted for connection .at one of its ends to 8 a ball to be retrieved and at .its other end to the periphery of said drum, said line being of a length at least sufiicient to extend from said drum to the ground when said drum is mounted in vertically spaced relation to the ground; and

(6) means for detachably connecting the bight at the other end of said elastomeric band to said drum supporting means at a point spaced from said drum along the projected axis of rotation thereof, said means comprising a metallic member having a first portion secured to said elastomeric band and a second portion detachably engageable with said drum supporting means whereby a desired length of said line may be unwound from said drum without placing said elastomeric band in tension, and a predetermined degree of initial tension can be introduced into said band by adjusting the position of said metallic 'member relative to said drum supporting means.

3. An automatic ball retrieving device comprising:

(a) a drum;

(b) vertical standard means rotatably supporting said drum and adapted to be'extended upwardly from the ground to support said drum vertically spaced from the ground; 7

(c) a rubber band connected to said drum for driving said drum in rotation;

(d) a flexible line reeled upon said drum and having a free end extending therefrom and adapted for connection to a ball, said flexible line being of a length to position said ball either on the ground or vertically spaced therefrom; and

(8) means for introducing a predetermined degree of initial tension lying within a selected range of tensions into said rubber band whereby a ball supported at the free end of said flexible line can be supported atvariable distances from said drum with the concurrent introduction of a minimum amount of tension into said rubber band. I

4. An automatic ball retrieving device as claimed in claim 3 and further characterised by including a ratchet device adjacent said drum and mounted on said means for rotatably supporting said drum, said ratchet device cooperating with said drum for precluding rotation of the drum in one direction, and said ratchet device further cooperating with said tension introducing means to permit a greater torque to be transmitted to said drum by said tension introducing means than by said ball whereby said ball may be positioned at a desired vertical level between the drum and the ground regardless of the setting of said tension introducing means.

References Cited by the Examiner UNITED STATES PATENTS 1,527,716 2/25 Tippen et a1. 273198 1,609,211 11/26 Sladek 46-206 XR 1,670,290 5/28 Aldrich 273198 1,907,412 5/33 Zimmer.

2,250,171 7/41 Wilkins 242107.3' 2,293,755 8/42 Joabson 242107.3 2,549,668 4/51 Cox 46206 XR 2,606,025 8/52 Hornig 273- XR 2,862,712 12/58 Delia et al 273198 XR OTHER REFERENCES The Sunday Star, Washington, D.C.,'Apr. 10, 1949, Mutt and Jet]? Comic strip.

DELBERT B. LOWE, Primary Examiner. 

1. AN AUTOMATIC BALL RETRIEVING DEVICE COMPRISING: (A) A DRUM; (B) MEANS ROTATABLY SUPPORTING SAID DRUM VERTICALLY SPACED FROM THE GROUND; (C) A TENSIONABLE ELONGATED MEMBER CONNECTED AT ONE OF ITS ENDS TO SAID DRUM FOR DRIVING SAID DRUM IN ROTATION; (D) A LINE ADAPTED TO BE CONNECTED AT ONE OF ITS ENDS TO THE BALL TO BE RETRIEVED AND CONNECTED AT ITS OTHER END TO THE PERIPHERY OF SAID DRUM, SAID LINE BEING OF A LENGTH SUCH THAT THE LINE CAN BE EXTENDED FROM SAID DRUM TO THE GROUND; AND (E) MEANS FOR INTRODUCING A PREDETERMINED DEGREE OF INITIAL TENSION INTO SAID TENSIONABLE MEMBER WHEREBY A BALL CONNECTED TO ONE END OF SAID LINE AND SUPPORTED BY SAID LINE CAN BE SUPPORTED AT VARIABLE DISTANCES FROM SAID DRUM AND ABOVE THE GROUND IN PLAYING A VARIETY OF DIFFERENT GAMES WITH DIFFERENT TYPES OF BALLS. 